Optimistic Planning for Markov Decision Processes

International audienceThe reinforcement learning community has recently intensified its interest in online planning methods, due to their relative independence on the state space size. However, tight near-optimality guarantees are not yet available for the general case of stochastic Markov decision processes and closed-loop, state-dependent planning policies. We therefore consider an algorithm related to AO* that optimistically explores a tree representation of the space of closed-loop policies, and we analyze the near-optimality of the action it returns after n tree node expansions. While this optimistic planning requires a finite number of actions and possible next states for each transition, its asymptotic performance does not depend directly on these numbers, but only on the subset of nodes that significantly impact near-optimal policies. We characterize this set by introducing a novel measure of problem complexity, called the near-optimality exponent. Specializing the exponent and performance bound for some interesting classes of MDPs illustrates the algorithm works better when there are fewer near-optimal policies and less uniform transition probabilities

Factor Structure, Validity and Reliability of the Intolerance of Uncertainty Scale -12 (IUS-12) in a Greek Undergraduate Sample

Intolerance of Uncertainty (IU) is described as the tendency to avoid uncertain states and exhibit negative responses to uncertain situations on cognitive, emotional, and behavioral levels. It is considered a transdiagnostic cognitive bias that plays a role in developing and maintaining psychopathology. The Intolerance of Uncertainty Scale-12 (IUS-12) has proven to be a sound measure of intolerance of uncertainty with excellent validity and reliability. Although research has supported a two-factor structure of IUS-12, most recent studies also suggest a bifactor model. The present study examines the factorial structure, validity, and reliability of the Greek version of IUS-12 with a sample of 959 university students (66.6% female) aged 19.63 years (SD = 3.20). Confirmatory Factor Analysis showed that although the two-factor solution adequately fit the data, the bifactor model better fit with IU total as an underlying one-factor. Internal consistency and validity were excellent for the total IUS-12 and Prospective and Inhibitory Anxiety subscales. Our findings support recent findings concerning the factorial structure of IUS-12 and the scale’s psychometric qualities in a Greek undergraduate sample. We expect that future research with clinical samples will confirm the screening and clinical utility of IUS-12

A Cross-Sectional Study of How Harm Avoidance, Incompleteness and Intolerance of Uncertainty Contribute to Obsessive–Compulsive Disorder in University Students

Research suggests that certain cognitive factors increase the likelihood of developing and maintaining obsessive–compulsive disorder (OCD). Such factors that are often associated with OCD are harm avoidance (HA), incompleteness (INC), and intolerance of uncertainty (IU). The present study aimed to examine the associations of intolerance of uncertainty, incompleteness, and harm avoidance with dimensions of obsessive–compulsive symptoms. Participants were 1128 university students (Mage = 19.42 St.d. = 2.02). Results showed that all subscales of the OCI-R correlated significantly with HA, INC, and IU, confirming the findings of previous studies. HA and INC appear to predict OC symptoms in a significant way. IU appears to correlate and improve the models, although to a lesser degree. The present findings contribute to our better understanding of the relationship between OCD symptoms and underlying cognitive variables and the nature of OCD heterogeneity

A Randomised Controlled CBT Intervention for Maladaptive Perfectionism: Outcome and Predictors

Maladaptive perfectionism has been associated with certain mental health problems. Moreover, studies suggest that the development of perfectionism can be attributed to childhood experiences and, more specifically, to parenting styles. (1) Background: The aims of the present study were first to examine the relationship of perfectionism to perceived parenting and current symptoms of depression and anxiety and, secondly, to study the effectiveness of a group CBT intervention program for high perfectionism; (2) Methods: Participants were 81 young Greek adults with relatively high scores in perfectionism. They were randomly allocated to two conditions: either the intervention group (IG; n = 40) or a non-active control group (CG; n = 41). The intervention group received a CBT intervention of 10 weekly sessions, while assessments were made in two time points for both groups; (3) Results: There was significant correlation of perfectionism with perceived parental indifference, abuse, and overcontrol as well as measures of anxiety and depression. Results showed significant decrease in perfectionism and other symptoms in the IG. Although perceived paternal indifference and abuse could predict perfectionism at pre-intervention, no pre-intervention variable could predict the perfectionism intervention outcome; (4) Conclusions: Overall, the study suggests that maladaptive perfectionism is associated with perceived negative parenting and current anxiety and depression and that a group CBT intervention can address specific dimensions of maladaptive perfectionism

A smart KPI system for reinforcing sustainable urban mobility plans under pandemic crises

The latest worldwide application of social distancing measures highlighted dramatic effects on the daily life, mobility, well-being, mental health, and economic activity of citizens during the pandemic. Unfortunately, societies were unprepared to confront a pandemic and applied movement restriction measures, often harsh and unbalanced, creating confusion, uncertainty, and annoyance to communities. In this paper, we reviewed a wide array of databases to categorise the mobility management measures implemented internationally in response to the social distancing restrictions that had to be taken during the first wave of the COVID-19 pandemic. Furthermore, to comprehensively assess the measures implemented to contain the COVID-19 pandemic from the perspective of the local community, we conducted focus group interviews with specific population groups that may have been affected to a greater extent. These groups consisted of vulnerable road users, such as mobility-impaired people and people who are facing severe health problems, representatives of the local economy and businesses and representatives of institutional stakeholders and policymakers. Our research showed that in the post-pandemic era, accessibility and not mobility should be at the heart of economic and social welfare. At the same time, the assurance of physical activity, which is strongly associated with the mental health of citizens, and the protection of the local economy are issues of outermost importance. However, local authorities were unprepared to manage these issues and often made fragmented and punitive decisions. By recognising the need for a regional or metropolitan emergency mechanism, this study aims to introduce a new system of indicators specifically adapted to the particularities and challenges encountered during the pandemic, accounts for local communities' unique needs and requirements, and complies with the general principles of Sustainable Urban Mobility Plans (SUMPs). In the future, the SUMP methodology should be revised to be able to handle and manage mobility systems under pandemic conditions

A short-form version of the Intolerance of Uncertainty Scale: Initial development of the IUS-5

Intolerance of Uncertainty (IU) is an individual´s "tendency to be bothered or upset by the (as yet) unknown elements of a situation, whether the possible outcome is negative or not." This construct, originally proposed in the context of Generalised Anxiety Disorder (GAD), is now considered a transdiagnostic construct. The Intolerance of Uncertainty Scale (IUS; Freeston, Rhéaume, Letarte, Dugas, & Ladouceur, 1994) has been the gold standard measure for IU, both the original 27-item and the 12-item (IUS-12; Carleton, Norton, & Asmundson, 2007) versions. The present study, conducted in the context of a broader research project about IU and the COVID-pandemic by the UNiCORN team, aims to develop an even shorter version of the IUS, both psychometrically sound and quicker to administer, which would increase its utility in research studies with an elevated number of measures. Initial analyses conducted in currently available data from four countries (UK, Italy, Spain and Greece) suggest that it is possible to reduce the IUS-12 to 5 items, including two items measuring desire for predictability, one item assessing uncertainty paralysis, and two items describing aversiveness of uncertainty. The five-item version of the questionnaire (IUS-5) showed adequate internal consistency across languages (English, Italian, Spanish, Greek) and across situations (e.g., before and during COVID-19), and its total score is highly correlated with the total score of the IUS-12. Overall, preliminary results suggest that the IUS-5 may represent a valid and reliable measure of IU to be used across samples, languages, and countries